1. Field of the Invention
The invention relates to a support of a microphone in an electronic device such as a mobile phone.
2. Description of the Related Art
In an electronic device such as a mobile phone and a video-camera set, a microphone is encased in a main case. It is important for such a microphone that it is supported in a main case so as not to receive vibration from the main case.
In order to ensure a microphone to be free of vibration, a conventional microphone was encased in a main case with the microphone being encased in a rubber-holder. The compliance (elastic deformation) of the rubber-holder prevents vibration from transferring to the microphone from the main case.
FIG. 1A is a front view of a conventional mobile phone, and FIG. 1B is a cross-sectional view taken along the line IB-IB.
As illustrated in FIGS. 1A and 1B, the illustrated conventional mobile phone is comprised of a microphone 101, a microphone holder 102 holding the microphone 101 therein, a main case 103 encasing the microphone holder 102 therein, a printed wiring board 104 for controlling operation of the mobile phone, a receiver 105 supported on the printed wiring board 104 with a holder 111 being sandwiched therebetween, a liquid crystal display device 107, and an antenna 108.
The main case 103 is formed with a voice-opening 106 in alignment with the receiver 105.
The microphone holder 102 is sandwiched between an inner surface of the main case 103 and the printed wiring board 104.
The microphone 101 is electrically connected to the printed wiring board 104 through electrically conductive elastomer 109 filled in an opening formed at a bottom of the microphone holder 102.
The microphone 101 makes air-communication with outside of the main case 103 through both an opening formed at an upper wall of the microphone holder 102 and a microphone-opening 110 formed at an upper wall of the main case 103.
For instance, Japanese Patent Application Publication No. 10-65775 has suggested a mobile phone including a microphone holder which makes point-contact with a microphone in order to prevent the microphone from receiving vibration caused by howling or a user. In the Publication, a microphone-opening is defined by a main case.
A main case of an electronic device such as a mobile phone is usually composed of a material having relatively high rigidity, such as a mold, and hence, tends to receive external vibration. In the mobile phone illustrated in FIGS. 1A and 1B, since the microphone-opening 110 is formed at the main case 103, vibration is transferred to the microphone 101 from the main case 103 through the microphone-opening 110.
Accordingly, though the microphone holder 102 is composed of elastic material, vibration caused at the main case 102 is not sufficiently cut off.
The mobile phone suggested in Japanese Patent Application Publication No. 10-65775 is accompanied with the same problem as mentioned above, because the microphone-opening is defined at the main case 103.
In addition, since the microphone holder 102 encasing the microphone 101 therein is sandwiched between the printed wiring board 104 and the main case 103, the microphone holder 102 is pressurized by them. As a result, the microphone holder 102 cannot keep compliance, and accordingly, the microphone 101 is likely to receive external vibration.
The mobile phone suggested in Japanese Patent Application Publication No. 10-65775 is accompanied with the same problem as mentioned above, because the microphone is pressurized in an area at which the microphone holder makes point-contact with the microphone.
Japanese Patent Application Publication No. 62-146079 has suggested a video-camera set including a case, a camera, a rotary head recorder, and a non-directional microphone. The camera and the recorder are encased in the case. The non-directional microphone is disposed at the center of a front panel in which a lens of the camera is arranged.
Japanese Patent Application Publication No. 10-23121 has suggested a phone including a case formed with a plurality of microphone-openings through which voice is transferred to a microphone.